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International Journal of Medical Laboratory
Shahid Sadoughi University of Medical Sciences
Fri, Apr 26, 2024
[Archive]
Volume 6, Issue 4 (November 2019)
IJML 2019, 6(4): 259-265 |
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Nayeri Chegeni T, Ghaffarifar F, Pirestani M, khoshzaban F, Dalimi Asl A, Maspi N. Genotyping of Acanthamoeba Species Isolated from Keratitis Patients by PCR Sequencing Methods in Tehran, Iran. IJML 2019; 6 (4) :259-265
URL: http://ijml.ssu.ac.ir/article-1-297-en.html
URL: http://ijml.ssu.ac.ir/article-1-297-en.html
Tooran Nayeri Chegeni 
, Fatemeh Ghaffarifar * , Majid Pirestani , Fariba Khoshzaban , Abdolhossein Dalimi Asl , Nahid Maspi
, Fatemeh Ghaffarifar * , Majid Pirestani , Fariba Khoshzaban , Abdolhossein Dalimi Asl , Nahid Maspi
Department of Parasitology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
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Discussion
[1]. Jones D, Visvesvara G, Robinson N. Acanthamoeba polyphaga keratitis and Acanthamoeba uveitis associated with fatal meningoencephalitis. Trans Ophthalmol Soc UK. 1975; 95(2): 221-32.
[2]. Martinez A, Janitschke K. Acanthamoeba, an opportunistic microorganism: a review. Infection 1985; 13(6): 251-56.
[3]. Schuster FL, Visvesvara GS. Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals. Int J Parasitol. 2004; 34(9): 1001-1027.
[4]. Marciano-Cabral F, Cabral G. Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev. 2003; 16(2): 273-307.
[5]. Parmar DN, Awwad ST, Petroll WM, Bowman RW, McCulley JP, Cavanagh HD. Tandem scanning confocal corneal microscopy in the diagnosis of suspected Acanthamoeba keratitis. Ophthalmology 2006; 113(4): 538-47.
[6]. Moreira AT, Prajna NV. Acanthamoeba as a cause of peripheral ulcerative keratitis. Cornea 2003; 22(6): 576-77.
[7]. Radford C, Minassian D, Dart J. Acanthamoeba keratitis in England and Wales: incidence, outcome, and risk factors. Br J Ophthalmol. 2002; 86(5): 536-42.
[8]. Rezaeian M, Farnia S, Niyyati M, Rahimi F. Amoebic keratitis in Iran (1997-2007). Iran J Parasitol. 2007; 2(3): 1-6.
[9]. Khan NA. Pathogenesis of Acanthamoeba infections. Microb Pathog. 2003; 34(6): 277-85.
[10]. Yera H, Zamfir O, Bourcier T, Ancelle T, Batellier L, Dupouy-Camet J, et al. Comparison of PCR, microscopic examination and culture for the early diagnosis and characterization of Acanthamoeba isolates from ocular infections. Eur J Clin Microbiol Infect Dis. 2007; 26(3): 221-24.
[11]. Booton GC, Kelly DJ, Chu YW, Seal DV, Houang E, Lam DS, et al. 18S ribosomal DNA typing and tracking of Acanthamoeba species isolates from corneal scrape specimens, contact lenses, lens cases, and home water supplies of Acanthamoeba keratitis patients in Hong Kong. J Clin Microbiol. 2002; 40(5): 1621-625.
[12]. Lehmann OJ, Green SM, Morlet N, Kilvington S, Keys MF, Matheson MM, et al. Polymerase chain reaction analysis of corneal epithelial and tear samples in the diagnosis of Acanthamoeba keratitis. Invest Ophthalmol Vis Sci. 1998; 39(7): 1261-265.
[13]. Khoshzaban F, Jabarvand M, Rezaeian M, Hashemian R. PCR application in diagnosis of Acanthamoeba keratitis. Iran J Ophthalmol. 2004; 1(1): 30-36.
[14]. Hammersmith KM. Diagnosis and manage-ment of Acanthamoeba keratitis. Curr Opin Ophthalmol. 2006; 17(4): 327-31.
[15]. Gautom RK, Fritsche TR, Lindquist TD. Acanthamoeba keratitis, In: W. Tasman and E. A. Jaeger (ed.), Philadelphia: Lippincott-Raven, Duane’s foundations of clinical ophthalmology; 1997: 2. p.1-15.
[16]. Qvarnstrom Y, Nerad TA, Visvesvara GS. Characterization of a new pathogenic Acantha-moeba species, A. byersi n. sp., isolated from a human with fatal amoebic encephalitis. J Eukaryot Microbiol. 2013; 60(6): 626-33.
[17]. Corsaro D, Walochnik J, Köhsler M, Rott MB. Acanthamoeba misidentification and multiple labels: redefining genotypes T16, T19, and T20 and proposal for Acanthamoeba micheli sp. nov.(genotype T19). Parasitol Res. 2015; 114(7): 2481-490.
[18]. Maghsood AH, Sissons J, Rezaian M, Nolder D, Warhurst D, Khan NA. Acanthamoeba genotype T4 from the UK and Iran and isolation of the T2 genotype from clinical isolates. J Med Microbiol. 2005; 54(8): 755-59.
[19]. Niyyati M, Lorenzo-Morales J, Rezaie S, Rahimi F, Mohebali M, Maghsood AH, et al. Genotyping of Acanthamoeba isolates from clinical and environmental specimens in Iran. Exp Parasitol. 2009; 121(3): 242-45.
[20]. Kao PM, Hsu BM, Chen CT. Identification and quantification of the Acanthamoeba species and genotypes from reservoirs in Taiwan by molecular techniques. Acta Trop. 2014; 132(1): 45-50.
[21]. Kao PM, Chou MY, Tao CW. Diversity and seasonal impact of Acanthamoeba species in a subtropical rivershed. Biomed Res Int. 2013; 112(1): 1131-136.
[22]. Tanveer T, Hameed A, Muazzam A, Jung SY, Gul A, Matin A. Isolation and molecular characterization of potentially pathogenic Acanthamoeba genotypes from diverse water resources including household drinking water from Khyber Pakhtunkhwa, Pakistan. Parasitol Res. 2013; 112(8): 2925-932.
[23]. Rezaeian M, Niyyati M, Farnia S, Haghi AM. Isolation of Acanthamoeba spp. from different environmental sources. Iran J Parasitol. 2008; 3 (1): 44-7.
[24]. Schroeder JM, Booton GC, Hay J, Niszl IA, Seal DV, Markus MB, et al. Use of subgenic 18S ribosomal DNA PCR and sequencing for genus and genotype identification of Acanthamoebae from humans with keratitis and from sewage sludge. J Clin Microbiol. 2001; 39(5): 1903-911.
[25]. Nuprasert W, Putaporntip C, Pariyakanok L, Jongwutiwes S. Identification of a novel T17 genotype of Acanthamoeba from environmental isolates and T10 genotype causing keratitis in Thailand. J Clin Microbiol. 2010; 48(12): 4636-640.
[26]. Ledee DR, Iovieno A, Miller D, Mandal N, Diaz M, Fell J, et al. Molecular identification of T4 and T5 genotypes in isolates from Acanthamoeba keratitis patients. J Clin Microbiol. 2009; 47(5): 1458-462.
[27]. Yera H, Zamfir O, Bourcier T, Viscogliosi E, Noël C, Dupouy J, et al. The genotypic characterisation of Acanthamoeba isolates from human ocular samples. Br J Ophthalmol. 2008; 92(8): 1139-141.
[28]. Zhang Y, Sun X, Wang Z, Li R, Luo S, Jin X, et al. Identification of 18S ribosomal DNA genotype of Acanthamoeba from patients with keratitis in North China. Invest Ophthalmol Vis Sci. 2004; 45(6): 1904-907.
[29]. Mirjalali H, Niyyati M, Abedkhojasteh H, Babaei Z, Sharifdini M, Rezaeian M. Pathogenic assays of Acanthamoeba belonging to the T4 genotype. Iran J Parasitol. 2013; 8(4): 530-37.
[30]. Ghamilouie M, Rahimi F, Khoshzaban F, Aghighi Z, Hassan N. Isolation and genotyping of Acanthamoeba strains from corneal scraps. Iran J Ophthalmol. 2014; 26(1): 97-101.
[31]. Niyyati M, Saberi R, Latifi A, Lasjerdi Z. Distribution of Acanthamoeba genotypes isolated from recreational and therapeutic geothermal water sources in southwestern Iran. Environ Health Insights 2016; 19(10): 69-74.
[32]. Behnia M, Hatam-Nahavandi K, Hajialilo E, Niyyati M, Tarighi F, Bakhtiar Akram A, et al. Occurrence of Acanthamoeba genotypes in wastewater samples in Tehran, Iran. Iran J Parasitol. 2017; 12(4): 516-21.
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Introduction
Acanthamoeba is a unicellular amphizoic opportunistic and pathogenic protozoon inducing keratitis in the eyes and fatal granulomatous encephalitis [1, 2]. Acantha-moeba has a broad distribution across the globe and is separated from various environmental sources [3]. The life cycle of Acanthamoeba consists of infective trophozoite living on various bacteria and resistant cysts stage and causingadverse conditions [4, 5]. The first signs of Acanthamoeba keratitis (AK) are redness with inflammation, photophobia, edema, epithelial defects and loss, pain, ring infiltration of corneal tissue and finally loss of vision [6, 7]. In Iran, the highest number of AK has been reported in contact lens wearers. Rezaian et al. reported that most of AK patients in Iran are the women 15 to 25 years old [8]. Increase of Acanthamoeba infections is possibly because of the increase in population of the contact lens users and the human immunodeficiency viruses patients [9]. AK is detected by several methods such as microscopic observation, culture and DNA-based methods [10, 11]. Microscopic observation and DNA-based methods can provide early diagnosis of Acanthamoeba [10, 12, 13]. Diagnosis is difficult and the disease can be confused with herpes simplex, adenovirus or fungal keratitis [14]. Successful treatments of ocular infections include cationic antiseptic that inhibits the membrane functions, aromatic diamidines inhibiting DNA synthesis, and polyenes such as amphotericin B [15]. Studies conducted in Iran indicate three species of Acanthamoeba related to keratitis including Acanthamoeba castellanii (T4), Acanthamoeba griffini (T3) and Acanthamoeba palestinensis (T2) [16]. Acanthamoeba has 20 genotypes (T1–T20) based on analysis of diagnostic fragment sequence of 18S rRNA gene [17]. T4 is the most common genotype observed in AK [18, 19]. Therefore, the aim of this study was to identify the frequency of the genotypes of Acanthamoeba in clinical samples in Tehran.
Materials and Methods
Sample collection and histological study
Thirty-five samples (corneal scraping, corneal biopsy, tear, and contact lens) were collected from patients with amoebic keratitis who had referred to Bina Afarin eye clinic during 4 years in Tehran, Iran. All samples in page's saline were transferred to the department of parasitology, faculty of medical sciences, Tarbiat Modares University, Tehran, Iran. The study was approved by the Ethics Committee of Tarbiat Modares University, Tehran, Iran.
DNA extraction and polymerase chain reaction (PCR)
Samples were cultured on non-nutrient agar (NNA) plates enriched with Escherichia coli bacteria strain K12. The plates were sealed and incubated at 30˚C for one month. Amoebae in plates were washed using phosphate-buffered saline (PBS). The resulting solution was then transferred into a microtube of 1.5 ml and centrifuged at 4000×rpm for 10 min. Subsequently, the supernatant was removed and and PBS was added and centrifugation was repeated. Finally, DNA extraction was performed using a DNGTM-PLUS (Cinna colon, Iran) according to the manufacturer’s instructions, and DNA stored at -20°C. A 461 bp region of the 18S rRNA gene was amplified using the genus-specific primers
JDP1 5'-GGCCCAGATCGTTTACCGTGAA-3' and JDP2 5'-TCTCACAAGCTGCTAGGGGAGTCA-3' (Takapozist, Iran) [20-22]. The PCR cycle profile was as the following: initial denaturation at 95°C for 5 min, followed by 35 cycles of denaturation at 95°C for 1 min, annealing at 61°C for 1 min and extension at 72°C for 1 min, with a final extension at 72°C for 10 min. Instead of the DNA, distilled water was used in a negative control.
Sequencing and phylogenetic analysis
PCR products were electrophoresed on 1.5% agarose gels containing SYBR safe DNA gel stain (Cinna colon, Iran) and were visualized under UV illumination. A 100-bp DNA ladder was used as a DNA size marker. PCR products of eight isolates were purified using Gent Bio purification kit (Tabasmed, Iran) and sequenced by Pishgam company (Iran). The obtained sequences were aligned using Chromas software (version 2.33). The genus and genotype of the species were identified according to the highest similarity to the genes found in the GenBank database [23, 24]. Identity levels of the sequences were compared with other Acanthamoeba species in GenBank using CLUSTAL OMEGA. Phylogenetic maximum likelihood reconstructions were performed using the phylogenetic program MEGA version 6. Evolutionary distances were computed using the Kimura two-parameter distance algorithm, and the bootstrap consensus tree was inferred from 1000 replicates. Phylogenetic trees were generated using maximum likelihood methods in MEGA6. The DNA sequences for the new isolates were deposited in the GenBank genetic sequence database at the National Center for Biotechnical Information (NCBI) under accession numbers KU877548, KU877549, KU877550, KU877551, KU877552, KU877553, KU877554, KU877555.
Results
Eight clinical specimens were positive for Acanthamoeba using genus specific primers. The samples collected from keratitis patients included 3 men (37.5%) and 5 women (62.5%) with the age range of 20 to 72 years (mean 36 years). Five patients (62.5%) had soft contact lenses or used self-made solutions and three patients (37.5%) had a history of trauma with the eye. All specimens were reported as genotype T4. PCR amplification revealed a fragment about 461 base pair (Fig. 1).
Sequencing and homology analysis of the obtained sequences in Basic Local Alignment Search Tool (BLAST) showed all Acanthamoeba strains belonging to the potentially pathogenic T4 genotype (Identity 99-100%) (Table 1) which is most common in human infections. The phylogeny tree was drawn with samples recorded in the Gene Bank (T1, T2, T3, T4, T5, T6, T10, T11, T13, T15, T16 and T17) sequenced samples in this study (n=8) thus showing the similarity of samples with those recorded in the Gene Bank (Fig. 2).
Materials and Methods
Sample collection and histological study
Thirty-five samples (corneal scraping, corneal biopsy, tear, and contact lens) were collected from patients with amoebic keratitis who had referred to Bina Afarin eye clinic during 4 years in Tehran, Iran. All samples in page's saline were transferred to the department of parasitology, faculty of medical sciences, Tarbiat Modares University, Tehran, Iran. The study was approved by the Ethics Committee of Tarbiat Modares University, Tehran, Iran.
DNA extraction and polymerase chain reaction (PCR)
Samples were cultured on non-nutrient agar (NNA) plates enriched with Escherichia coli bacteria strain K12. The plates were sealed and incubated at 30˚C for one month. Amoebae in plates were washed using phosphate-buffered saline (PBS). The resulting solution was then transferred into a microtube of 1.5 ml and centrifuged at 4000×rpm for 10 min. Subsequently, the supernatant was removed and and PBS was added and centrifugation was repeated. Finally, DNA extraction was performed using a DNGTM-PLUS (Cinna colon, Iran) according to the manufacturer’s instructions, and DNA stored at -20°C. A 461 bp region of the 18S rRNA gene was amplified using the genus-specific primers
JDP1 5'-GGCCCAGATCGTTTACCGTGAA-3' and JDP2 5'-TCTCACAAGCTGCTAGGGGAGTCA-3' (Takapozist, Iran) [20-22]. The PCR cycle profile was as the following: initial denaturation at 95°C for 5 min, followed by 35 cycles of denaturation at 95°C for 1 min, annealing at 61°C for 1 min and extension at 72°C for 1 min, with a final extension at 72°C for 10 min. Instead of the DNA, distilled water was used in a negative control.
Sequencing and phylogenetic analysis
PCR products were electrophoresed on 1.5% agarose gels containing SYBR safe DNA gel stain (Cinna colon, Iran) and were visualized under UV illumination. A 100-bp DNA ladder was used as a DNA size marker. PCR products of eight isolates were purified using Gent Bio purification kit (Tabasmed, Iran) and sequenced by Pishgam company (Iran). The obtained sequences were aligned using Chromas software (version 2.33). The genus and genotype of the species were identified according to the highest similarity to the genes found in the GenBank database [23, 24]. Identity levels of the sequences were compared with other Acanthamoeba species in GenBank using CLUSTAL OMEGA. Phylogenetic maximum likelihood reconstructions were performed using the phylogenetic program MEGA version 6. Evolutionary distances were computed using the Kimura two-parameter distance algorithm, and the bootstrap consensus tree was inferred from 1000 replicates. Phylogenetic trees were generated using maximum likelihood methods in MEGA6. The DNA sequences for the new isolates were deposited in the GenBank genetic sequence database at the National Center for Biotechnical Information (NCBI) under accession numbers KU877548, KU877549, KU877550, KU877551, KU877552, KU877553, KU877554, KU877555.
Results
Eight clinical specimens were positive for Acanthamoeba using genus specific primers. The samples collected from keratitis patients included 3 men (37.5%) and 5 women (62.5%) with the age range of 20 to 72 years (mean 36 years). Five patients (62.5%) had soft contact lenses or used self-made solutions and three patients (37.5%) had a history of trauma with the eye. All specimens were reported as genotype T4. PCR amplification revealed a fragment about 461 base pair (Fig. 1).
Sequencing and homology analysis of the obtained sequences in Basic Local Alignment Search Tool (BLAST) showed all Acanthamoeba strains belonging to the potentially pathogenic T4 genotype (Identity 99-100%) (Table 1) which is most common in human infections. The phylogeny tree was drawn with samples recorded in the Gene Bank (T1, T2, T3, T4, T5, T6, T10, T11, T13, T15, T16 and T17) sequenced samples in this study (n=8) thus showing the similarity of samples with those recorded in the Gene Bank (Fig. 2).
Table 1. Genotypes of Acanthamoeba isolates obtained from keratitis patients
| Isolates code | Culture | PCR | Genotype | Accession number |
| 1 | + | + | T4 | KU877548 |
| 2 | + | + | T4 | KU877549 |
| 3 | + | + | T4 | KU877550 |
| 4 | + | + | T4 | KU877551 |
| 5 | + | + | T4 | KU877552 |
| 6 | + | + | T4 | KU877553 |
| 7 | + | + | T4 | KU877554 |
| 8 | + | + | T4 | KU877555 |
Discussion
In the previous studies, different genotypes such as T2, T3, T4 and T6 were separated from environmental samples, amoebic keratitis, granulomatous encephalitis, and skin wounds whereas some other genotypes such as T10 were not separated from clinical specimens [25].
In this study, all positive samples belonged to T4 genotype the results of which are consistent with the findings of previous studies [11, 26-28]. T4 has been confirmed as a predominant Acanthamoeba genotype in AK. The main reason of abundant cases due to T4 genotype is unclear yet and some researchers have noted that one of the reasons of its global distribution and high transmission is its dominant genotype [29]. The present study revealed that eight specimens of patients referring to Bina Afarin eye clinic in Tehran were infected with Acanthamoeba spp. In a study by Ghamilouie et al. (2014), five clinical samples (5.6%) of 89 specimens collected from keratitis patients and sequence analysis demonstrated that T4 is the dominant genotype in these isolates and the primary genotype in AK [30]. Another study by Maghsood et al. (2005) reported 13 clinical cases with acanthamoebiasis in which eight out of 13 cases were T4, two out of 13 cases were T3, and three out of 13 were T2 genotype [18]. The T4 genotype is also most prevalent in environmental samples; a study had shown the contamination of geothermal water samples with an average temperature of 30-50°C by Acanthamoeba in southwestern Iran. The contamination was estimated to be up to 50%. Genotyping of the diagnostic fragment showed 15 isolates (93.75%), which belonged to the T4 genotype and a single strain labeled as T2 genotype [31]. Another research in raw wastewater treatment facilities in west and south of Tehran detected Acanthamoeba belonging to T4 (83%) and T11 (17%) genotypes [32].
Conclusion
T4 is the most prevalent genotype related to parasitic infection of cornea by Acanthamoeba in Iran and worldwide. Furthere molecular studies are needed to specify the distribution of Acanthamoeba genotypes and the actual prevalence of the keratitis. The aim of this study was to determine the prevalence and genotype of AK in the patients who had referred to Bina Afarin Eye clinic in Tehran because of the incidence of potentially pathogenic Acanthamoeba. T4 genotype in AK patients can be a serious threat for high-risk individuals such as contact lens users. Thus, to prevent the contamination, higher hygiene considerations are recommended.
Conflict of Interest
There is no conflict to declare.
Acknowledgments
We would like to thank the staff of the department of parasitology in Tarbiat Modares University for their help with this research. Thanks to Dr. Bita Bakhshi, the associate professor of medical bacteriology for his sincere cooperation in this project.
References
In this study, all positive samples belonged to T4 genotype the results of which are consistent with the findings of previous studies [11, 26-28]. T4 has been confirmed as a predominant Acanthamoeba genotype in AK. The main reason of abundant cases due to T4 genotype is unclear yet and some researchers have noted that one of the reasons of its global distribution and high transmission is its dominant genotype [29]. The present study revealed that eight specimens of patients referring to Bina Afarin eye clinic in Tehran were infected with Acanthamoeba spp. In a study by Ghamilouie et al. (2014), five clinical samples (5.6%) of 89 specimens collected from keratitis patients and sequence analysis demonstrated that T4 is the dominant genotype in these isolates and the primary genotype in AK [30]. Another study by Maghsood et al. (2005) reported 13 clinical cases with acanthamoebiasis in which eight out of 13 cases were T4, two out of 13 cases were T3, and three out of 13 were T2 genotype [18]. The T4 genotype is also most prevalent in environmental samples; a study had shown the contamination of geothermal water samples with an average temperature of 30-50°C by Acanthamoeba in southwestern Iran. The contamination was estimated to be up to 50%. Genotyping of the diagnostic fragment showed 15 isolates (93.75%), which belonged to the T4 genotype and a single strain labeled as T2 genotype [31]. Another research in raw wastewater treatment facilities in west and south of Tehran detected Acanthamoeba belonging to T4 (83%) and T11 (17%) genotypes [32].
Conclusion
T4 is the most prevalent genotype related to parasitic infection of cornea by Acanthamoeba in Iran and worldwide. Furthere molecular studies are needed to specify the distribution of Acanthamoeba genotypes and the actual prevalence of the keratitis. The aim of this study was to determine the prevalence and genotype of AK in the patients who had referred to Bina Afarin Eye clinic in Tehran because of the incidence of potentially pathogenic Acanthamoeba. T4 genotype in AK patients can be a serious threat for high-risk individuals such as contact lens users. Thus, to prevent the contamination, higher hygiene considerations are recommended.
Conflict of Interest
There is no conflict to declare.
Acknowledgments
We would like to thank the staff of the department of parasitology in Tarbiat Modares University for their help with this research. Thanks to Dr. Bita Bakhshi, the associate professor of medical bacteriology for his sincere cooperation in this project.
References
[1]. Jones D, Visvesvara G, Robinson N. Acanthamoeba polyphaga keratitis and Acanthamoeba uveitis associated with fatal meningoencephalitis. Trans Ophthalmol Soc UK. 1975; 95(2): 221-32.
[2]. Martinez A, Janitschke K. Acanthamoeba, an opportunistic microorganism: a review. Infection 1985; 13(6): 251-56.
[3]. Schuster FL, Visvesvara GS. Free-living amoebae as opportunistic and non-opportunistic pathogens of humans and animals. Int J Parasitol. 2004; 34(9): 1001-1027.
[4]. Marciano-Cabral F, Cabral G. Acanthamoeba spp. as agents of disease in humans. Clin Microbiol Rev. 2003; 16(2): 273-307.
[5]. Parmar DN, Awwad ST, Petroll WM, Bowman RW, McCulley JP, Cavanagh HD. Tandem scanning confocal corneal microscopy in the diagnosis of suspected Acanthamoeba keratitis. Ophthalmology 2006; 113(4): 538-47.
[6]. Moreira AT, Prajna NV. Acanthamoeba as a cause of peripheral ulcerative keratitis. Cornea 2003; 22(6): 576-77.
[7]. Radford C, Minassian D, Dart J. Acanthamoeba keratitis in England and Wales: incidence, outcome, and risk factors. Br J Ophthalmol. 2002; 86(5): 536-42.
[8]. Rezaeian M, Farnia S, Niyyati M, Rahimi F. Amoebic keratitis in Iran (1997-2007). Iran J Parasitol. 2007; 2(3): 1-6.
[9]. Khan NA. Pathogenesis of Acanthamoeba infections. Microb Pathog. 2003; 34(6): 277-85.
[10]. Yera H, Zamfir O, Bourcier T, Ancelle T, Batellier L, Dupouy-Camet J, et al. Comparison of PCR, microscopic examination and culture for the early diagnosis and characterization of Acanthamoeba isolates from ocular infections. Eur J Clin Microbiol Infect Dis. 2007; 26(3): 221-24.
[11]. Booton GC, Kelly DJ, Chu YW, Seal DV, Houang E, Lam DS, et al. 18S ribosomal DNA typing and tracking of Acanthamoeba species isolates from corneal scrape specimens, contact lenses, lens cases, and home water supplies of Acanthamoeba keratitis patients in Hong Kong. J Clin Microbiol. 2002; 40(5): 1621-625.
[12]. Lehmann OJ, Green SM, Morlet N, Kilvington S, Keys MF, Matheson MM, et al. Polymerase chain reaction analysis of corneal epithelial and tear samples in the diagnosis of Acanthamoeba keratitis. Invest Ophthalmol Vis Sci. 1998; 39(7): 1261-265.
[13]. Khoshzaban F, Jabarvand M, Rezaeian M, Hashemian R. PCR application in diagnosis of Acanthamoeba keratitis. Iran J Ophthalmol. 2004; 1(1): 30-36.
[14]. Hammersmith KM. Diagnosis and manage-ment of Acanthamoeba keratitis. Curr Opin Ophthalmol. 2006; 17(4): 327-31.
[15]. Gautom RK, Fritsche TR, Lindquist TD. Acanthamoeba keratitis, In: W. Tasman and E. A. Jaeger (ed.), Philadelphia: Lippincott-Raven, Duane’s foundations of clinical ophthalmology; 1997: 2. p.1-15.
[16]. Qvarnstrom Y, Nerad TA, Visvesvara GS. Characterization of a new pathogenic Acantha-moeba species, A. byersi n. sp., isolated from a human with fatal amoebic encephalitis. J Eukaryot Microbiol. 2013; 60(6): 626-33.
[17]. Corsaro D, Walochnik J, Köhsler M, Rott MB. Acanthamoeba misidentification and multiple labels: redefining genotypes T16, T19, and T20 and proposal for Acanthamoeba micheli sp. nov.(genotype T19). Parasitol Res. 2015; 114(7): 2481-490.
[18]. Maghsood AH, Sissons J, Rezaian M, Nolder D, Warhurst D, Khan NA. Acanthamoeba genotype T4 from the UK and Iran and isolation of the T2 genotype from clinical isolates. J Med Microbiol. 2005; 54(8): 755-59.
[19]. Niyyati M, Lorenzo-Morales J, Rezaie S, Rahimi F, Mohebali M, Maghsood AH, et al. Genotyping of Acanthamoeba isolates from clinical and environmental specimens in Iran. Exp Parasitol. 2009; 121(3): 242-45.
[20]. Kao PM, Hsu BM, Chen CT. Identification and quantification of the Acanthamoeba species and genotypes from reservoirs in Taiwan by molecular techniques. Acta Trop. 2014; 132(1): 45-50.
[21]. Kao PM, Chou MY, Tao CW. Diversity and seasonal impact of Acanthamoeba species in a subtropical rivershed. Biomed Res Int. 2013; 112(1): 1131-136.
[22]. Tanveer T, Hameed A, Muazzam A, Jung SY, Gul A, Matin A. Isolation and molecular characterization of potentially pathogenic Acanthamoeba genotypes from diverse water resources including household drinking water from Khyber Pakhtunkhwa, Pakistan. Parasitol Res. 2013; 112(8): 2925-932.
[23]. Rezaeian M, Niyyati M, Farnia S, Haghi AM. Isolation of Acanthamoeba spp. from different environmental sources. Iran J Parasitol. 2008; 3 (1): 44-7.
[24]. Schroeder JM, Booton GC, Hay J, Niszl IA, Seal DV, Markus MB, et al. Use of subgenic 18S ribosomal DNA PCR and sequencing for genus and genotype identification of Acanthamoebae from humans with keratitis and from sewage sludge. J Clin Microbiol. 2001; 39(5): 1903-911.
[25]. Nuprasert W, Putaporntip C, Pariyakanok L, Jongwutiwes S. Identification of a novel T17 genotype of Acanthamoeba from environmental isolates and T10 genotype causing keratitis in Thailand. J Clin Microbiol. 2010; 48(12): 4636-640.
[26]. Ledee DR, Iovieno A, Miller D, Mandal N, Diaz M, Fell J, et al. Molecular identification of T4 and T5 genotypes in isolates from Acanthamoeba keratitis patients. J Clin Microbiol. 2009; 47(5): 1458-462.
[27]. Yera H, Zamfir O, Bourcier T, Viscogliosi E, Noël C, Dupouy J, et al. The genotypic characterisation of Acanthamoeba isolates from human ocular samples. Br J Ophthalmol. 2008; 92(8): 1139-141.
[28]. Zhang Y, Sun X, Wang Z, Li R, Luo S, Jin X, et al. Identification of 18S ribosomal DNA genotype of Acanthamoeba from patients with keratitis in North China. Invest Ophthalmol Vis Sci. 2004; 45(6): 1904-907.
[29]. Mirjalali H, Niyyati M, Abedkhojasteh H, Babaei Z, Sharifdini M, Rezaeian M. Pathogenic assays of Acanthamoeba belonging to the T4 genotype. Iran J Parasitol. 2013; 8(4): 530-37.
[30]. Ghamilouie M, Rahimi F, Khoshzaban F, Aghighi Z, Hassan N. Isolation and genotyping of Acanthamoeba strains from corneal scraps. Iran J Ophthalmol. 2014; 26(1): 97-101.
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Type of Study: Research |
Subject:
Parasitology
Received: 2019/01/28 | Accepted: 2019/07/2 | Published: 2019/11/1
Received: 2019/01/28 | Accepted: 2019/07/2 | Published: 2019/11/1
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